I'm sorry, but if I find something worth keeping out of the water, I'm going to do it. Rule of thumb is that if it will look good on display somewhere in my house its mine.
Actually, this isn't always legal.
There are a couple of things to keep in mind
1) Ownership
This is closely related to the status of a wreck. A wreck that's been declared or defaulted to derelict can be picked clean at the diver's discretion.
However, not all wrecks are derelicts.
A ship has an owner, the cargo has an owner and the insurance companies (there may be more than one) have claim (salvage rights) on the ship and/or the cargo for a certain length of time after the wreck goes down. If you take something from a wreck while it is still in ownership of another party then youÃÓe effectively stealing. Depending on what you take the owner may not be amused.
Secondly, the ownership of wrecks may go through several stages but even if the owner of the ship and the insurance companies decide to write off their loss then the ownership of the wreck may default to the government. This is the case, for example, in Canada, where the government effectively claims ownership of all wrecks in her territorial waters. The government may decide to restrict diving on certain objects for various reasons which may also include restrictions on salvage taking. In the US I *suspect* but IÃÎ not sure, that this probably a matter thatÃÔ organised on the state level so before you salvage items a wreck you should look into the status of the wreck.
Finally, when you do find something of value (a treasure, for example), even if the wreck is derelict then the seedy side of people (and governments) will certainly surface and you may (and if the cargo is very valuable, almost certainly will) be sued by someone who will try to take it away from you, whether they have any proper legal claim to it or not. Items from some famous shipwrecks like the Titanic fall into this category, as do most expensive cargos such as cargos of gold the point being here, know what youÃÓe taking or risk getting more stress piled on you than itÃÔ worth.
2) special status
Some wrecks are given special status. War wrecks, for example, sometimes have the status of war-graves, which protects them from looting and may protect them from other activities as well. The British, for example, have declared all war ships as war-graves and while youÃÓe free to dive on them you are not permitted to salvage anything, remove human remains or photograph human remains.
A government may also declare a wreck off limits to diving for archaeological purposes. For example, if we suddenly discover NoahÃÔ Arc somewhere, IÃÎ sure we will not be permitted to dive on it. Other significant wrecks also have similar restrictions.
IÃÎ personally not against taking things if you have a right to them (most wrecks are just junk anyway) but I want to point that out because itÃÔ easy to say online that youÃÍl take whatever you darned well feel like taking (or to get the impression from a post like this that people are ok with this attitude). However, this attitude actually does more harm to the diving community than good. In some cases it takes a lot of time and effort to get the owners of wrecks to agree to let divers on them and it only takes one clown with a *me* *me* *me* attitude to ruin it for everyone.
R..